import Menu from "ant-design-vue/es/menu";
import Icon from "ant-design-vue/es/icon";

export default {
  name: "SMenu",
  props: {
    menu: {
      type: Array,
      required: true
    },
    theme: {
      type: String,
      required: false,
      default: "dark"
    },
    mode: {
      type: String,
      required: false,
      default: "inline"
    },
    collapsed: {
      type: Boolean,
      required: false,
      default: false
    }
  },
  data() {
    return {
      openKeys: [],
      selectedKeys: [],
      cachedOpenKeys: []
    };
  },
  computed: {
    rootSubmenuKeys: vm => {
      const keys = [];
      vm.menu.forEach(item => keys.push(item.path));
      return keys;
    }
  },
  mounted() {
    this.updateMenu();
  },
  watch: {
    collapsed(val) {
      if (val) {
        this.cachedOpenKeys = this.openKeys.concat();
        this.openKeys = [];
      } else {
        this.openKeys = this.cachedOpenKeys;
      }
    },
    $route: function() {
      this.updateMenu();
    }
  },
  methods: {
    // select menu item
    onOpenChange(openKeys) {
      // 在水平模式下时执行，并且不再执行后续
      if (this.mode === "horizontal") {
        this.openKeys = openKeys;
        return;
      }
      // 非水平模式时
      const latestOpenKey = openKeys.find(key => !this.openKeys.includes(key));
      if (!this.rootSubmenuKeys.includes(latestOpenKey)) {
        this.openKeys = openKeys;
      } else {
        this.openKeys = latestOpenKey ? [latestOpenKey] : [];
      }
    },
    onSelect({ item, key, selectedKeys }) {
      this.selectedKeys = selectedKeys;
      this.$emit("select", { item, key, selectedKeys });
    },
    updateMenu() {
      const routes = this.$route.matched.concat();
      const { hidden } = this.$route.meta;
      if (routes.length >= 3 && hidden) {
        routes.pop();
        this.selectedKeys = [routes[routes.length - 1].path];
      } else {
        this.selectedKeys = [routes.pop().path];
      }
      const openKeys = [];
      if (this.mode === "inline") {
        routes.forEach(item => {
          openKeys.push(item.path);
        });
      }

      this.collapsed
        ? (this.cachedOpenKeys = openKeys)
        : (this.openKeys = openKeys);
    },

    // render
    renderItem(menu) {
      if (!menu.hidden) {
        return menu.children && !menu.hideChildrenInMenu
          ? this.renderSubMenu(menu)
          : this.renderMenuItem(menu);
      }
      return null;
    },
    renderMenuItem(menu) {
      const target = menu.meta.target || null;
      const CustomTag = (target && "a") || "router-link";
      const props = { to: { name: menu.name } };
      const attrs = { href: menu.path, target: menu.meta.target };

      if (menu.children && menu.hideChildrenInMenu) {
        // 把有子菜单的 并且 父菜单是要隐藏子菜单的
        // 都给子菜单增加一个 hidden 属性
        // 用来给刷新页面时， selectedKeys 做控制用
        menu.children.forEach(item => {
          item.meta = Object.assign(item.meta, { hidden: true });
        });
      }

      return (
        <Menu.Item {...{ key: menu.path }}>
          <CustomTag {...{ props, attrs }}>
            {this.renderIcon(menu.meta.icon)}
            <span>{menu.meta.title}</span>
          </CustomTag>
        </Menu.Item>
      );
    },
    renderSubMenu(menu) {
      const itemArr = [];
      if (!menu.hideChildrenInMenu) {
        menu.children.forEach(item => itemArr.push(this.renderItem(item)));
      }
      return (
        <Menu.SubMenu {...{ key: menu.path }}>
          <span slot="title">
            {this.renderIcon(menu.meta.icon)}
            <span>{menu.meta.title}</span>
          </span>
          {itemArr}
        </Menu.SubMenu>
      );
    },
    renderIcon(icon) {
      if (icon === "none" || icon === undefined) {
        return null;
      }
      const props = {};
      typeof icon === "object" ? (props.component = icon) : (props.type = icon);
      return <Icon {...{ props }} />;
    }
  },

  render() {
    const dynamicProps = {
      props: {
        mode: this.mode,
        theme: this.theme,
        openKeys: this.openKeys,
        selectedKeys: this.selectedKeys
      },
      on: {
        openChange: this.onOpenChange,
        select: this.onSelect
      }
    };

    const menuTree = this.menu.map(item => {
      if (item.hidden) {
        return null;
      }
      return this.renderItem(item);
    });

    return <Menu {...dynamicProps}>{menuTree}</Menu>;
  }
};
